What I don't get is why did all EVERY single NFL player and owner's little bird brains seize up in a panic and decide that it would be smartest to make a show of "unity" against Trump by kneeling? How are they all so uniformly dumb?

I think it was mostly the players and their view of the world likely comes from their twitter feed. It is pretty easy to come to the conclusion that everyone in the country hates Trump if your "news" comes from mainstream media and social media.